JP2014160547A - Radiation generating tube and radiation photography system using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radiation generating tube having high position accuracy by accurately aligning positions of a target and a lens electrode that controls an electron beam emitted from an electron emission source during assembly and suppressing a positional deviation after assembly.SOLUTION: A cathode unit 10 having an electron emission source 11, an extraction electrode 13, and a lens electrode 14 and an anode unit 20 having a target 22 and a shield member 21 are mutually bonded through a columnar spacer 30.

Description

  The present invention relates to a radiation generating tube applied to diagnostic applications and non-destructive X-ray imaging in the fields of medical equipment and industrial equipment, and a radiation imaging system using the same.

  In general, a radiation generating tube equipped with a control electrode system guides thermionic electrons emitted from an electron emission source such as a filament to the control electrode system, controls the trajectory of the electrons, and collides with the desired position of the target. Radiation is generated from the target. The generated radiation passes through the target and is irradiated to the irradiated object, and photographing is performed (see Patent Document 1). In addition to the basic configuration described above, unnecessary radiation and reflected electrons are shielded and heat radiation characteristics are improved by installing a shielding member for radiation and reflected electrons immediately before the target that generates radiation. (See Patent Document 2).

  In the radiation generating tube having the above-described configuration, it is necessary to position the control electrode system and the target with high accuracy in order to cause the electrons to collide with a desired position of the target without causing the electrons to collide with the shielding member. That is, the positioning of each component of the radiation generating tube is positioning for electrons to collide with a desired position on the target surface through a desired trajectory.

  Usually, in the control electrode system, the plurality of electrodes are arranged such that the center of the aperture diameter of the electrode through which electrons pass is located on the same axis (opening axis). The center of gravity of the electron beam, which is an electron aggregate, moves along the axis, and the electron beam is emitted from the control electrode system. Thereafter, the target is irradiated with the electron beam through the axis (opening axis) of the opening of the shielding member disposed immediately before the target. Therefore, it is necessary to accurately position the opening axis of the control electrode system and the opening axis of the shielding member.

  In conventionally known radiation generating tubes, in many cases, a cathode unit including an electron emission source and an anode unit including a target and a shielding member are separately fixed to an envelope. An example is shown in FIG. In the figure, reference numeral 10 denotes a cathode unit, which includes an electron emission source 11, an extraction electrode 13, and a lens electrode 14, and is attached to the envelope 40 by a support member 61 via a holding member 12 that holds the electron emission source 11. . An anode unit 20 includes a target 22 and a shielding member 21 and is attached to an opening provided on one wall surface of the envelope 40, and constitutes a part of the wall surface of the envelope 40.

  As described above, in the configuration in which the cathode unit 10 and the anode unit 20 are respectively attached to the envelope 40, the opening 14a of the lens electrode 14 that is a control electrode system and the opening 21a of the shielding member 21 are provided. The positional relationship depends on the processing accuracy of the envelope 40. Further, when the envelope 40 is deformed due to a temperature change during the operation of the radiation generating tube, the positional relationship between the opening 14a of the lens electrode 14 and the opening 21a of the shielding member 21 is also affected. .

  In the technique disclosed in Patent Literature 3, a jig for directly connecting the anode unit and the cathode unit to the envelope is sandwiched until immediately before the anode unit and the cathode unit are fixed separately, thereby processing the envelope at the time of assembly. Achieves alignment that does not depend on accuracy.

JP 2009-245727 A JP 2009-205992 A JP 2012-79449 A

  As described above, according to the technique of Patent Document 3, it is possible to align the opening axis of the control electrode system and the opening axis of the shielding member without depending on the processing accuracy of the envelope. However, in the configuration in which the cathode unit including the control electrode system and the anode unit including the shielding member are attached to the envelope, the deformation of the envelope due to the temperature change during the operation of the radiation generating tube after the assembly is not accurate. It remains the same.

  It is an object of the present invention to accurately align the target constituting the radiation generating tube and the lens electrode that controls the electron beam emitted from the electron emission source at the time of assembly, and to suppress positional deviation after assembly. An object of the present invention is to provide a radiation generating tube with high positional accuracy. Furthermore, it is providing the radiography system which can obtain a highly accurate image using such a radiation generating tube.

According to a first aspect of the present invention, a cathode unit including an electron emission source, a target that emits radiation when irradiated with electrons emitted from the electron emission source, and a radiation shielding member disposed around the target are provided. A radiation generating tube having an anode unit,
The cathode unit and the anode unit are joined to each other via a plurality of columnar spacers.

A second aspect of the present invention is the radiation generating tube of the present invention,
A radiation detector for detecting radiation emitted from the radiation generating tube and transmitted through the subject;
A radiation imaging system comprising: a control device that controls the radiation generating tube and the radiation detection device in a coordinated manner.

  In the present invention, since the cathode unit and the anode unit are joined via the spacer, the cathode unit and the anode unit can be attached to the envelope in the joined state with the spacer joined at the time of assembly. That is, since the radiation generating tube is assembled in a state where the opening axis of the lens electrode included in the cathode unit and the opening axis of the light shielding member included in the anode unit are directly aligned, highly accurate alignment is realized. Furthermore, even when a positional deviation occurs in one of the cathode unit and the anode unit due to thermal deformation of the envelope during operation of the radiation generating tube, the other follows the positional deviation via the spacer. The deviation is reduced more than the positional deviation. Therefore, in the present invention, a radiation generating tube is provided that is aligned with high accuracy during assembling and that is prevented from being displaced during operation. Furthermore, by using such a radiation generating tube, a radiation imaging system capable of obtaining a highly accurate image is provided.

(A) is a cross-sectional schematic diagram of 1st Embodiment of the radiation generating tube of this invention, (b) is a cross-sectional schematic diagram of the other structural example of an anode unit. In this invention, it is a perspective view which shows typically a mode that the cathode unit and the anode unit were joined via the spacer. It is a cross-sectional schematic diagram of 2nd Embodiment of the radiation generating tube of this invention. It is a cross-sectional schematic diagram of 3rd Embodiment of the radiation generating tube of this invention. It is 4th Embodiment of the radiation generating tube of this invention, and is a cross-sectional schematic diagram of the structure which has multiple electron emission sources. It is a schematic diagram which shows the shape of the columnar spacer used for this invention, (a) is the perspective view of the example, (b) is sectional drawing of another example. It is a schematic diagram which shows the structure of an example of the anode unit which concerns on this invention, (a) is the perspective view, (b) is A-A 'sectional drawing of (a). It is a schematic diagram which shows the structure of an example of the anode unit which concerns on this invention, (a) is the perspective view, (b) is A-A 'sectional drawing of (a). It is a figure which shows one Embodiment of the radiography system of this invention. It is a cross-sectional schematic diagram which shows the structural example of the conventional radiation generating tube.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. The dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention only to them.

Embodiment 1
FIG. 1A is a schematic cross-sectional view of the first embodiment of the radiation generating tube of the present invention. The cathode unit 10 includes an electron emission source 11, an extraction electrode 13, and a lens electrode 14. The electron emission source 11 is held by a holding member 12, and the holding member 12 and the extraction electrode 13, and the extraction electrode 13 and the lens electrode 14 are joined to each other by electrically insulating spacers 51 and 52. The holding member 12 is attached to the envelope 40 by a support member 61.

  The electron emission source 11 may be a thermionic emission source in which an electron emission material and a heater are combined, or may be a cold cathode such as a field emitter. The extraction electrode 13 includes an opening 13a through which the electrons 71 emitted from the electron emission source 11 pass, and the lens electrode 14 has an opening 14a through which the electrons 71 that have passed through the opening 13a of the extraction electrode 13 pass. have. As a constituent material of the holding member 12, the extraction electrode 13, and the lens electrode 14, molybdenum which is generally a refractory metal and has low outgassing in a vacuum is preferably used. In order to insulate the holding member 12 from the electron emission source 11, an insulating layer such as an alumina layer is interposed between the holding member 12 and the electron emission source 11. As the spacers 51 and 52 for joining the holding member 12, the extraction electrode 13, and the lens electrode 14 to each other, an insulating member such as alumina is used.

  The anode unit 20 includes a target 22 and a radiation shielding member 21 disposed around the target 22. The target 22 includes a target film 22a and a target substrate 22b on which the target film 22a is formed. The material of the target film 22a is not particularly limited, but tungsten or molybdenum is often used, and the film The thickness is about 1 μm to 10 μm. Since the target film 22a is irradiated with an electron beam having a high energy density, the target substrate 22b preferably has a high thermal conductivity in order to improve heat dissipation. For example, a diamond substrate having a thickness of 0.5 mm to 5 mm is preferably used. Use. Further, in order to ensure the positional accuracy of the target 22, the target substrate 22b is preferably made of a highly rigid material and structure.

  The shielding member 21 is a member that shields the component of the radiation and reflected electrons generated at the target 22 from the rear, that is, toward the cathode unit 10, and also has a heat dissipation function. As a material having a radiation shielding function, oxygen-free copper is preferably used. As shown in FIG. 1B, a tungsten layer 21b having a radiation shielding function superior to copper is disposed on the inner peripheral side in contact with the target 22. It is preferable. A copper layer 21c having a higher thermal conductivity than tungsten is provided on the outer periphery of the tungsten layer 21b to maintain the heat dissipation function. When the anode unit 20 constitutes a part of the wall surface of the envelope 40 as shown in FIG. 1A, the tungsten layer 21b and the copper layer 21c need to be airtight so that they can be held in vacuum. In consideration of airtightness and thermal conductivity, for example, silver brazing is preferably used for joining.

  The envelope 40 functions to keep the space through which the electrons 71 pass in a vacuum. Here, the target substrate 22b and the shielding member 21 may be exposed to the atmosphere side, and may be a part of an airtight wall of the envelope 40 as in the present embodiment. The envelope 40 may be a conductive member or an electrically insulating member. However, when the envelope 40 is a conductive member and an opening is provided on one wall surface, and one of the cathode unit 10 and the anode unit 20 is attached to the opening, the one not attached to the opening is insulative. It attaches to the envelope 40 using the support member.

  In the present embodiment, the anode unit 20 is attached to an opening provided in the envelope 40, and the cathode unit 10 is joined to the envelope 40 via a support member 61. Therefore, when the envelope 40 is made of a conductive member, the support member 61 is made of an insulating member. SUS304 is preferably used as the conductive member used in the envelope 40, and alumina is preferably used as the insulating member. As for the insulating support member 61, alumina is preferably used. When the envelope 40 is a conductive member, the envelope 40 and the anode unit 20 have the same potential. Usually, the target 22 is set to the ground potential via the shielding member 21. Therefore, when the anode unit 20 is attached to the opening of the envelope 40 as in the present embodiment and the envelope 40 is formed of a conductive member, the target 22 is grounded by grounding the envelope 40. It can be. The support member 61 may be attached to the envelope 40 by screwing to the inner wall or by welding. In addition, the insulating support member 61 is preferably provided with unevenness in the longitudinal direction on the side surface, so that the creeping distance becomes longer than the length of the support member 61 and prevents creeping discharge.

  In the present invention, it is a structural feature that the cathode unit 10 and the anode unit 20 are joined to each other via a columnar spacer 30. Specifically, the cathode unit 10 and the anode unit 20 are joined via a plurality of spacers 30 as shown in FIGS. The spacer 30 is attached to the shielding member 21 with respect to the anode unit 20.

  In the case of FIG. 2A, spacers 30 are arranged on both sides with the electron emission source 11 as the center. When the planar shape of the cathode unit 10 is circular as shown in FIG. 2B, three spacers 30 are used, and the spacers 30 are arranged at the apexes of a triangle including the centers of the electron emission source 11 and the target 22 inside. Deploy.

  When attaching the spacer 30, two or more reference points are provided on the shielding member 21 of the anode unit 20, and the reference points corresponding to the reference points are any of the holding member 12, the extraction electrode 13, and the lens electrode 14 of the cathode unit 10. Set up. The reference point of the anode unit 20 and the reference point of the cathode unit 10 form a pair, and each pair is joined through the same number of spacers 30 as the pair. The positional relationship between the shielding member 21 and the target 22 in the anode unit 20 and the positional relationship between the holding member 12 or the extraction electrode 13 or the lens electrode 14 and the electron emission source 11 in the cathode unit 10 are guaranteed by processing accuracy and assembly accuracy. And Since the optical axis of the electrons 71 emitted from the electron emission source 11 is greatly influenced by the position of the lens electrode 14, the reference point of the cathode unit 10 is provided on the lens electrode 14, that is, the spacer 30 is joined to the lens electrode 14. Is preferred.

  In the present embodiment, the cathode unit 10 and the anode unit 20 and the spacer 30 are joined by the single electron emission source 11 and the distance between the spacers 30 is narrow, and the influence of thermal deformation of the envelope 40 is slight. Fix with silver brazing or adhesive. The spacer 30 is insulative, and preferably insulative ceramics, specifically alumina. The side surface of the spacer 30 is preferably provided with irregularities in the longitudinal direction of the spacer 30, so that the creeping distance becomes longer than the length of the spacer 30 and the creeping discharge is prevented.

  In the present invention, since the cathode unit 10 and the anode unit 20 are joined via the spacer 30, the envelope 40 is in a state where the cathode unit 10 and the anode unit 20 are joined via the spacer 30 in advance. Can be attached to. Therefore, the opening axis of the lens electrode 14 of the cathode unit 10 and the opening axis of the shielding member 21 of the anode unit 20 can be aligned at the shortest distance, and high-accuracy alignment is realized. In addition, when attaching to the envelope 40, the envelope 40 and the anode unit 20 are joined by laser welding or the like so as not to affect the positional relationship between the cathode unit 10 and the anode unit 20 that have already been joined. Bonding is performed using a means that generates less distortion. Moreover, when the edge part of the shielding member 21 and the envelope 40 is a member which cannot be welded, it is necessary to join the member which can be welded beforehand. For example, when the envelope 40 is made of alumina, a Kovar material may be brazed to the opening end of the envelope 40 in advance.

  In the present invention, since the cathode unit 10 and the anode unit 20 are joined via the spacer 30, the alignment at the time of assembly is highly accurate. In addition, even if a positional deviation occurs in the opening 21 a of the shielding member 21, the cathode unit 10 follows the positional deviation of the anode unit 20 by the spacer 30. For this reason, the positional shift between the opening axis of the shielding member 21 and the opening axis of the lens electrode 14 caused by such positional shift is suppressed to be smaller than the positional shift of the opening 21a.

  In the present embodiment, the anode unit 20 is attached to the opening of the envelope 40, and the cathode unit 10 is attached to the envelope 40 via the insulating support member 61. good. That is, the cathode unit 10 is attached to an opening provided in the envelope 40, and the anode unit 20 is joined to the envelope 40 via a support member. At this time, when the envelope 40 is a conductive member, the anode unit 20 is joined to the envelope 40 via an insulating support member.

[Embodiment 2]
FIG. 3 shows a second embodiment of the present invention. The difference from the first embodiment is that both the cathode unit 10 and the anode unit 20 constitute part of the wall surface of the envelope 40. There is. That is, an opening is provided in each of two opposing wall surfaces of the envelope 40, the cathode unit 10 is attached to one opening, and the anode unit 20 is attached to the other opening. Except for this configuration, the second embodiment is the same as the first embodiment. In the present embodiment, either the conductive member or the insulating member is used as the envelope 40, but when the envelope 40 is a conductive member, at least one of the cathode unit 10 and the anode unit 20 is It joins to the envelope 40 through an insulating member.

[Embodiment 3]
FIG. 4 shows a third embodiment of the present invention. The difference from the first embodiment is that both the cathode unit 10 and the anode unit 20 are attached to the envelope 40 via support members 61 and 62. In the point. Except for this configuration, the second embodiment is the same as the first embodiment. In this embodiment, an opening is provided in the envelope 40 in advance, and the cathode unit 10 and the anode unit 20 are joined to each other through the spacer 30 and stored in the envelope 40 from the opening. The inside is hermetically sealed by sealing the opening with a corresponding lid. The support members 61 and 62 may be joined by any method that does not affect the positional relationship between the cathode unit 10 and the anode unit 20, and may be, for example, screwing the inner wall of the envelope 40 or welding. In this embodiment, either a conductive member or an insulating member is used as the envelope 40. However, when the envelope 40 is a conductive member, the support members 61 and 62 are insulating members. And

  In the present embodiment, since the anode unit 20 is inside the envelope 40, a window 80 that transmits the radiation generated by the target 22 to the outside of the envelope 40 is required. Specifically, a window made of, for example, beryllium is provided at a portion facing the opening 21a of the shielding member 21 of the envelope 40, so that both radiation transmission and vacuum airtightness can be ensured.

[Embodiment 4]
In the first to third embodiments, the case where the number of electron emission sources is one is shown. However, in the present invention, a configuration having a plurality of electron emission sources is also possible. In this case, the number of openings of the extraction electrode and the opening of the lens electrode may be equal to the number of electron emission sources or one for a plurality of electron emission sources. In the case of one, the electrons emitted from a plurality of electron emission sources are collectively controlled. The target is disposed corresponding to the openings of the extraction electrode and the lens electrode. When there are a plurality of electron emission sources, one opening for the extraction electrode and the lens electrode, and one target, one opening for the lens electrode and one for the shielding member as in the first to third embodiments. The opening is aligned with the opening.

  In the present embodiment, a mode in which a plurality of targets are irradiated with a plurality of electron emission sources controlled by a lead electrode provided with a plurality of openings and a lens electrode provided with a plurality of openings will be described. The constituent members other than those described below are the same as those in the first to third embodiments, and a description thereof will be omitted.

  FIG. 5 shows an embodiment having three electron emission sources 11 and three targets 22 each. In this case, three openings 13 a of the extraction electrode 13 and three openings 14 a of the lens electrode 14 are also formed corresponding to the electron emission source 11 and the target 22. The interval between two adjacent electron emission sources 11 is about 5 mm to 50 mm. The electron emission source 11 and the openings 13a and 14a are arranged in a row, and the spacers 30 are arranged at both ends in the arrangement direction. Note that the number of the electron emission sources 11 and the targets 22 is not limited to three, and may be any number as long as it is two or more. Further, the number of the spacers 30 is not limited to two, and may be three or more. However, with four or more, the distance between the cathode unit 10 and the anode unit 20 may not be uniquely determined. Book or three is preferred.

  The joining of the cathode unit 10 and the spacer 30 of the anode unit 20 is not fixed by silver brazing or an adhesive, but is performed by applying a fitting force between the protruding portion and the recessed portion and clamping the fitting portion. . This is because the influence of the heat change of the envelope 40 is large because there are a plurality of electron emission sources 11 and the distance between the two spacers 30 is wide.

  As shown in FIG. 6A, the spacer 30 used in the present embodiment has a cylindrical shape, has convex portions 30a at both ends, and has a flat portion 30b around the convex portion 30a. The distance between the surfaces of the flat portions 30a at both ends (the height of the cylinder) is 5 mm to 30 mm. Since the flat part 30b is in contact with the cathode unit 10 and the anode unit 20, the distance between the surfaces of the flat part 30b defines the distance between the cathode unit 10 and the anode unit 20. Further, the side surface of the spacer 30 may have a flat shape as shown in FIG. 6A or a shape with irregularities in the longitudinal direction as shown in FIG. Thus, by providing unevenness on the side surface of the spacer 30, the creeping distance from one flat portion 30b to the other flat portion 30b becomes longer than the inter-surface distance, which is preferable in preventing creeping discharge.

  The convex portion 30 a of the spacer 30 is fitted into a concave portion provided in the cathode unit 10 and the anode unit 20. Specifically, as shown in FIGS. 7 and 8, the anode unit 20 is provided with a recess 21 d corresponding to the protrusion 30 a of the spacer 30. The same applies to the cathode unit 10, and any one of the holding member 12, the extraction electrode 13, and the lens electrode 14 is provided with a recess similar to the recess 21 d in FIG. 4. 7B and 8B are schematic cross-sectional views in the vertical direction at the position A-A 'in FIGS. 7A and 8A. The recesses 21d correspond to the reference points described above, and when provided on the lens electrode 14, are provided at both ends in the arrangement direction of the openings 14a, and the shielding member 21 is provided at both ends in the arrangement direction of the openings 21a. .

  The convex portion 30a of the spacer 30 is formed so as to be fitted into a concave portion which is a reference point provided in the cathode unit 10 and the anode unit 20 with a gap of 0.01 mm to 0.1 mm. Thereby, the cathode unit 10 and the anode unit 20 can be joined with a positional accuracy of 0.01 mm to 0.1 mm.

  The flat portion 30b of the spacer 30 is in contact with the flat portion provided around the concave portion, which is a reference point provided in the cathode unit 10 and the anode unit 20, so that the parallelism between the cathode unit 10 and the anode unit 20 is achieved. It can be kept below a certain level. The parallelism is set to 0.02 mm to 0.1 mm. The parallelism can be expressed as a parallelism of the surface of the lens electrode 14 on the anode unit 20 side when the surface of the anode unit 20 on the cathode unit 10 side is used as a reference plane. The gap between the concave portion, which is a reference point provided in the cathode unit 10 and the anode unit 20, and the convex portion 30 a of the spacer 30 may serve as play for the shape change during the operation of the radiation generating tube 100. In some cases, even a gap of 0.1 mm is not sufficient, and shear stress is applied to the spacer 30. Assuming such a case, as shown in FIGS. 7 and 8, one of the two recesses 21d as the reference point provided in the anode unit 20 (the left side in FIG. 7 and FIG. 8) is long. As a hole, a play with respect to a shape change may be secured. In this case, the reference point of the oblong hole cannot fix the position of the opening 21a of the shielding member 21, but can prevent the displacement in the rotational direction. That is, in FIG. 7 and FIG. 8, the position of the opening 21a in the X direction cannot be fixed, but since there is little play in the Y direction, the rotation of the anode unit 20 in the XY plane is prevented.

  Also in the present embodiment, the anode unit 20 is configured such that the shielding member 21 includes the tungsten layer 21b and the copper layer 21c described in FIG. 1B in the first embodiment. In the present embodiment, as shown in FIG. 7, the inner circumference of each opening 21a is made of a tungsten layer 21b and the outer side thereof is made of a copper layer 21c. It is good also as a structure which made the tungsten layer 21b to comprise continue in all the opening parts 21a.

  In the present embodiment, the cathode unit 10 is joined to the envelope 40 via the support member 61, but the support member 61 also has a convex portion on one side of the cylindrical shape, and the convex portion is held by the holding member 12. The form which fits into the recessed part provided in is preferable. At this time, in the fitting portion between the support member 61 and the cathode unit 10, play can be secured by providing a gap of 0.5 mm to 2 mm.

  With the above configuration, the target of the radiation source and the electron emission source can be accurately aligned.

[Embodiment 5]
As described in the first to fourth embodiments, the radiation generating tube of the present invention is a transmissive radiation generating tube provided with a transmissive target. The radiation generating tube of the present invention is preferably applied to a radiation imaging system. Hereinafter, an embodiment of a radiation imaging system according to the present invention will be described with reference to FIG.

  As shown in FIG. 9, the radiation generating tube 100 of the present invention is incorporated in a radiation generating apparatus 200 together with a radiation driving circuit 101 that controls the driving thereof. The radiation 104 generated in the radiation generating tube 100 is emitted from the radiation emission window 102 of the radiation generating apparatus 200 to the outside. The movable aperture unit 103 provided in the radiation emission window 102 portion of the radiation generating apparatus 200 has a function of adjusting the width of the radiation field irradiated from the radiation generating tube 100. Further, as the movable diaphragm unit 103, a unit to which a function capable of simulating and displaying a radiation irradiation field with visible light can be used.

  The system control apparatus 202 controls the radiation generation apparatus 200 and the radiation detection apparatus 201 in cooperation with each other. The drive circuit 101 outputs various control signals to the radiation generating tube 100 under the control of the system control device 202. With this control signal, the radiation emitted from the radiation generation apparatus 200 passes through the subject 204 and is detected by the detector 206. The detector 206 converts the detected radiation into an image signal and outputs the image signal to the signal processing unit 205. The signal processing unit 205 performs predetermined signal processing on the image signal under the control of the system control device 202, and outputs the processed image signal to the system control device 202. The system control device 202 outputs a display signal for displaying an image on the display device 203 to the display device 203 based on the processed image signal. The display device 203 displays an image based on the display signal on the display as a captured image of the subject 204. A representative example of radiation is X-rays, and the radiation generating tube 100 and the radiation imaging system of the present invention can be used as an X-ray generation unit and an X-ray imaging system. The X-ray imaging system can be used for nondestructive inspection of industrial products and pathological diagnosis of human bodies and animals.

  In the present invention, since the alignment between the control electrode system and the target is performed with high accuracy in the radiation generating tube 100 and positional deviation during operation is suppressed, a highly accurate image can be obtained in the radiation imaging system. .

  10: cathode unit, 11: electron emission source, 12: holding member, 13: extraction electrode, 14: lens electrode, 20: anode unit, 21: shielding member, 21b: tungsten layer, 21c: copper layer, 22: target, 30: spacer, 40: envelope, 61, 62: support member, 71: electronic, 100: radiation generating tube, 104: radiation, 200: radiation generating apparatus, 201: radiation detecting apparatus, 202: system control apparatus, 204 : Subject

Claims (14)

Radiation having a cathode unit including an electron emission source, an anode unit including a target that emits radiation when irradiated with electrons emitted from the electron emission source, and a radiation shielding member disposed around the target. In the generator tube,
The radiation generating tube, wherein the cathode unit and the anode unit are joined to each other via a plurality of columnar spacers. The cathode unit has a holding member that holds the electron emission source, an extraction electrode that has an opening through which electrons emitted from the electron emission source pass and is joined to the holding member, and the electrons pass through the cathode unit. A lens electrode having an opening and bonded to the extraction electrode;
The radiation generating tube according to claim 1, wherein the spacer is bonded to the lens electrode and the shielding member.   The radiation generating tube according to claim 2, wherein the lens electrode is made of molybdenum.   4. The radiation generating tube according to claim 2, wherein the shielding member includes a tungsten layer positioned on an inner peripheral side in contact with the target and a copper layer positioned on an outer periphery of the tungsten layer. The cathode unit has a plurality of electron emission sources arranged in a row,
The anode unit has a plurality of targets arranged corresponding to each of the plurality of electron emission sources,
5. The radiation generating tube according to claim 1, wherein the spacers are disposed at both ends in the arrangement direction of the electron emission source of the cathode unit and the target of the anode unit. 6.   The radiation generating tube includes an envelope having openings on two wall surfaces facing each other, the cathode unit is attached to one opening, and the anode unit is attached to the other opening, respectively. The radiation generating tube according to any one of claims 1 to 5, wherein the inside is maintained in a vacuum.   The radiation generating tube according to claim 6, wherein the envelope is electrically insulating.   The radiation generating tube includes an envelope having an opening on one wall surface, one of the cathode unit and the anode unit is attached to the opening, and the inside of the envelope is held in a vacuum. The radiation generating tube according to any one of 1 to 5.   The radiation generating tube according to claim 8, wherein the envelope is conductive.   6. The radiation generator according to claim 1, wherein the radiation generating tube includes an envelope, the cathode unit and the anode unit are accommodated in the envelope, and the interior of the envelope is maintained in a vacuum. The radiation generating tube according to item 1.   The radiation generating tube according to claim 10, wherein the envelope is conductive.   The radiation generating tube according to any one of claims 1 to 11, wherein the spacer is made of insulating ceramics and has unevenness on a side surface in a longitudinal direction.   The radiation generating tube according to any one of claims 1 to 12, wherein the radiation generating tube is a transmissive radiation generating tube provided with a transmissive target. The radiation generating tube according to any one of claims 1 to 13,
A radiation detector for detecting radiation emitted from the radiation generating tube and transmitted through the subject;
A radiation imaging system comprising: a control device that controls the radiation generating tube and the radiation detection device in a coordinated manner.

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